Question: Express your answer as a mixed number simplified to lowest terms. $11\dfrac{9}{18}+9\dfrac{1}{18} = {?}$
Solution: Separate the whole numbers from the fractional parts: $= {11} + {\dfrac{9}{18}} + {9} + {\dfrac{1}{18}}$ Bring the whole numbers together and the fractions together: $= {11} + {9} + {\dfrac{9}{18}} + {\dfrac{1}{18}}$ Add the whole numbers: $=20 + {\dfrac{9}{18}} + {\dfrac{1}{18}}$ Add the fractions: $= 20+\dfrac{10}{18}$ Combine the whole and fractional parts into a mixed number: $= 20\dfrac{10}{18}$